Field of the Invention
This invention relates to an electric lawn mower control apparatus, particularly to an apparatus for controlling operation of a walk-behind electric lawn mower movable over a lawn growth area hand-pushed by a user.
Description of Related Art
A walk-behind electric lawn mower of this type ordinarily comprises an electric motor mounted on a frame hand-pushed by a user and supplied with operating electric power from a rechargeable battery and is constituted to cut lawn or grass by rotationally driving a blade cutter installed on the undersurface of the frame using the electric motor.
Legal regulations require the blade cutter of a lawn mower to be stopped within a stipulated time (3 seconds) after the user inputs a stop instruction. Lawn mowers with on-board engines are therefore equipped with a clutch and a mechanical brake so the blade cutter can be stopped within the stipulated time.
As for electric lawn mowers, they are equipped with an electric motor that can be stopped within the stipulated time by implementing regenerative braking. Notwithstanding, when rotational speed of the electric motor slows, stopping within the stipulated time becomes difficult because regenerative braking force weakens.
In this connection, Japanese Unexamined Patent Publication No. 2012-196104 teaches a motor drive apparatus that enables mechanical brake downsizing or elimination by short-circuiting the motor coil to achieve adequate baking force even in a battery full-charge state that disables regenerative braking.
Although, as stated above, the technology of the reference responds to the battery being in full-charge state by switching from regenerative braking to short-circuit braking, fail-safe stopping within the stipulated time is apt to be difficult to achieve by merely switching from regenerative braking to short-circuit braking.